1. Field
The present disclosure broadly relates to tools used to vacuum bag process composite parts, and deals more particularly with a composite tool having vacuum integrity.
2. Background
Vacuum bag processing is commonly used in the fabrication of composite parts to consolidate and/or cure a part layup comprising a multi-ply pre-preg. The part layup is placed on a tool and a vacuum bag is installed over the layup and sealed to the tool. The vacuum bag is evacuated in order to compress the layup against the tool and thereby consolidate and/or form the layup. Any leaks that may occur which allow a loss of vacuum bag pressure may affect the quality and/or performance of the finished part.
Composite tools are sometimes used for vacuum bag processing because of their relatively low cost to manufacture and light weight. However these composite tools may sometimes experience through-the-tool leaks which occur at the time of manufacture, or during service due to thermal cycling or impact damage caused by handling. Because of these problems, composite tools may be tested for air leak prior to use. When through-the-tool leaks are detected, the composite tool may be repaired, however such repairs are not always reliable, and some cases, if not performed properly, the repair itself may result in a leak. In some cases, leakages in composite tools may be temporarily repaired by placing a thermoplastic or similar tape over the facesheet of the tool, covering the area of the leak. However this type of repair may not be durable, and may affect the dimensional accuracy of the cured part.
Accordingly, there is a need for a composite tool used in vacuum bag processing of composite parts that reduces or eliminates through-the-tool leaks, and which is both durable and reliable. There is also a need for a method of fabricating a composite tool with the vacuum integrity of the type mentioned above.